Conventionally, copper wires made of copper or copper alloy having excellent electrical conductivity and strength have been used for a wiring harness wired in a vehicle. A copper terminal made of copper or copper alloy, which is the same type of metal as the copper wire, is crimped and connected to an end of the copper wire, and this copper terminal is connected to a device or the like.
In recent years, the weight of a vehicle has been further reduced to improve fuel economy and aluminum wires using aluminum or aluminum alloy as a conductive material have been used as wires to be arranged in the vehicle for the purpose of weight reduction. Although copper terminals made of copper or copper alloy, which is a different type of metal, are crimped and connected to ends of the aluminum wires in terms of strength and the like, the weight of the entire wiring harness is reduced by using the aluminum wires. Such a technique is known, for example, from Japanese Unexamined Patent Publication No. 2005-174896.
An aluminum wire similar to the above wire is used also for a relay terminal for connecting wires for the purpose of weight reduction in some cases. In such cases, the aluminum wire is connected to the relay terminal made of copper or copper alloy.
However, if a core of a wire and a terminal are formed of different types of metals in connecting the wire and the terminal, it is known that at least one of the two metals is dissolved in the form of ions into water and electrolytic corrosion, in which corrosion proceeds by an electrochemical reaction, occurs particularly when an electrolyte is present on a contact part of the wire and the terminal. In the case of the relay terminal as described above, if water or the like intrudes into one end connected to the aluminum wire from the other end, electrolytic corrosion possibly occurs in a part where the aluminum wire and the relay terminal are connected.
The present invention was completed based on the above situation and an object thereof is to suppress the progress of electrolytic corrosion in a part where different types of metals are connected.